USING ATOMIC FORCE MICROSCOPY TO PROBE BIOFILM-COHESION

摘要

An important physical characteristic of biofilms, such as those covering medical implants, is film cohesion. Because cohesion can be a primary factor affecting the balance between growth and detachment, its quantification is essential in understanding, predicting, and modeling biofilm development, whether on medical implants or waste water treatment media. But cohesion is one of the most difficult material properties to measure, even to define. From a physics viewpoint, the quantity would have fundamental units of energy per unit volume; that is, cohesive energy density. But it is more commonly probed as yield force per unit area, using some custom-built apparatus. Yield, however, is a nonequilibrium, threshold phenomenon; thus measured values depend on details such as rate, as well as difficult estimates of the true area over which force is imparted at the yield point.